// SPDX-License-Identifier: GPL-2.0
/*
 * Greybus "Core"
 *
 * Copyright 2014-2015 Google Inc.
 * Copyright 2014-2015 Linaro Ltd.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#define CREATE_TRACE_POINTS
#include <linux/greybus.h>
#include "greybus_trace.h"

#define GB_BUNDLE_AUTOSUSPEND_MS        3000

/* Allow greybus to be disabled at boot if needed */
static bool nogreybus;
#ifdef MODULE
module_param(nogreybus, bool, 0444);
#else
core_param(nogreybus, nogreybus, bool, 0444);
#endif
int greybus_disabled(void)
{
        return nogreybus;
}
EXPORT_SYMBOL_GPL(greybus_disabled);

static int is_gb_host_device(const struct device *dev)
{
        return dev->type == &greybus_hd_type;
}

static int is_gb_module(const struct device *dev)
{
        return dev->type == &greybus_module_type;
}

static int is_gb_interface(const struct device *dev)
{
        return dev->type == &greybus_interface_type;
}

static int is_gb_control(const struct device *dev)
{
        return dev->type == &greybus_control_type;
}

static int is_gb_bundle(const struct device *dev)
{
        return dev->type == &greybus_bundle_type;
}

static int is_gb_svc(const struct device *dev)
{
        return dev->type == &greybus_svc_type;
}

static bool greybus_match_one_id(struct gb_bundle *bundle,
                                 const struct greybus_bundle_id *id)
{
        if ((id->match_flags & GREYBUS_ID_MATCH_VENDOR) &&
            (id->vendor != bundle->intf->vendor_id))
                return false;

        if ((id->match_flags & GREYBUS_ID_MATCH_PRODUCT) &&
            (id->product != bundle->intf->product_id))
                return false;

        if ((id->match_flags & GREYBUS_ID_MATCH_CLASS) &&
            (id->class != bundle->class))
                return false;

        return true;
}

static const struct greybus_bundle_id *
greybus_match_id(struct gb_bundle *bundle, const struct greybus_bundle_id *id)
{
        if (!id)
                return NULL;

        for (; id->vendor || id->product || id->class || id->driver_info;
                                                                        id++) {
                if (greybus_match_one_id(bundle, id))
                        return id;
        }

        return NULL;
}

static int greybus_match_device(struct device *dev, const struct device_driver *drv)
{
        const struct greybus_driver *driver = to_greybus_driver(drv);
        struct gb_bundle *bundle;
        const struct greybus_bundle_id *id;

        if (!is_gb_bundle(dev))
                return 0;

        bundle = to_gb_bundle(dev);

        id = greybus_match_id(bundle, driver->id_table);
        if (id)
                return 1;
        /* FIXME - Dynamic ids? */
        return 0;
}

static int greybus_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
        const struct gb_host_device *hd;
        const struct gb_module *module = NULL;
        const struct gb_interface *intf = NULL;
        const struct gb_control *control = NULL;
        const struct gb_bundle *bundle = NULL;
        const struct gb_svc *svc = NULL;

        if (is_gb_host_device(dev)) {
                hd = to_gb_host_device(dev);
        } else if (is_gb_module(dev)) {
                module = to_gb_module(dev);
                hd = module->hd;
        } else if (is_gb_interface(dev)) {
                intf = to_gb_interface(dev);
                module = intf->module;
                hd = intf->hd;
        } else if (is_gb_control(dev)) {
                control = to_gb_control(dev);
                intf = control->intf;
                module = intf->module;
                hd = intf->hd;
        } else if (is_gb_bundle(dev)) {
                bundle = to_gb_bundle(dev);
                intf = bundle->intf;
                module = intf->module;
                hd = intf->hd;
        } else if (is_gb_svc(dev)) {
                svc = to_gb_svc(dev);
                hd = svc->hd;
        } else {
                dev_WARN(dev, "uevent for unknown greybus device \"type\"!\n");
                return -EINVAL;
        }

        if (add_uevent_var(env, "BUS=%u", hd->bus_id))
                return -ENOMEM;

        if (module) {
                if (add_uevent_var(env, "MODULE=%u", module->module_id))
                        return -ENOMEM;
        }

        if (intf) {
                if (add_uevent_var(env, "INTERFACE=%u", intf->interface_id))
                        return -ENOMEM;
                if (add_uevent_var(env, "GREYBUS_ID=%08x/%08x",
                                   intf->vendor_id, intf->product_id))
                        return -ENOMEM;
        }

        if (bundle) {
                // FIXME
                // add a uevent that can "load" a bundle type
                // This is what we need to bind a driver to so use the info
                // in gmod here as well

                if (add_uevent_var(env, "BUNDLE=%u", bundle->id))
                        return -ENOMEM;
                if (add_uevent_var(env, "BUNDLE_CLASS=%02x", bundle->class))
                        return -ENOMEM;
        }

        return 0;
}

static void greybus_shutdown(struct device *dev)
{
        if (is_gb_host_device(dev)) {
                struct gb_host_device *hd;

                hd = to_gb_host_device(dev);
                gb_hd_shutdown(hd);
        }
}

static int greybus_probe(struct device *dev)
{
        struct greybus_driver *driver = to_greybus_driver(dev->driver);
        struct gb_bundle *bundle = to_gb_bundle(dev);
        const struct greybus_bundle_id *id;
        int retval;

        /* match id */
        id = greybus_match_id(bundle, driver->id_table);
        if (!id)
                return -ENODEV;

        retval = pm_runtime_get_sync(&bundle->intf->dev);
        if (retval < 0) {
                pm_runtime_put_noidle(&bundle->intf->dev);
                return retval;
        }

        retval = gb_control_bundle_activate(bundle->intf->control, bundle->id);
        if (retval) {
                pm_runtime_put(&bundle->intf->dev);
                return retval;
        }

        /*
         * Unbound bundle devices are always deactivated. During probe, the
         * Runtime PM is set to enabled and active and the usage count is
         * incremented. If the driver supports runtime PM, it should call
         * pm_runtime_put() in its probe routine and pm_runtime_get_sync()
         * in remove routine.
         */
        pm_runtime_set_autosuspend_delay(dev, GB_BUNDLE_AUTOSUSPEND_MS);
        pm_runtime_use_autosuspend(dev);
        pm_runtime_get_noresume(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);

        retval = driver->probe(bundle, id);
        if (retval) {
                /*
                 * Catch buggy drivers that fail to destroy their connections.
                 */
                WARN_ON(!list_empty(&bundle->connections));

                gb_control_bundle_deactivate(bundle->intf->control, bundle->id);

                pm_runtime_disable(dev);
                pm_runtime_set_suspended(dev);
                pm_runtime_put_noidle(dev);
                pm_runtime_dont_use_autosuspend(dev);
                pm_runtime_put(&bundle->intf->dev);

                return retval;
        }

        pm_runtime_put(&bundle->intf->dev);

        return 0;
}

static void greybus_remove(struct device *dev)
{
        struct greybus_driver *driver = to_greybus_driver(dev->driver);
        struct gb_bundle *bundle = to_gb_bundle(dev);
        struct gb_connection *connection;
        int retval;

        retval = pm_runtime_get_sync(dev);
        if (retval < 0)
                dev_err(dev, "failed to resume bundle: %d\n", retval);

        /*
         * Disable (non-offloaded) connections early in case the interface is
         * already gone to avoid unceccessary operation timeouts during
         * driver disconnect. Otherwise, only disable incoming requests.
         */
        list_for_each_entry(connection, &bundle->connections, bundle_links) {
                if (gb_connection_is_offloaded(connection))
                        continue;

                if (bundle->intf->disconnected)
                        gb_connection_disable_forced(connection);
                else
                        gb_connection_disable_rx(connection);
        }

        driver->disconnect(bundle);

        /* Catch buggy drivers that fail to destroy their connections. */
        WARN_ON(!list_empty(&bundle->connections));

        if (!bundle->intf->disconnected)
                gb_control_bundle_deactivate(bundle->intf->control, bundle->id);

        pm_runtime_put_noidle(dev);
        pm_runtime_disable(dev);
        pm_runtime_set_suspended(dev);
        pm_runtime_dont_use_autosuspend(dev);
        pm_runtime_put_noidle(dev);
}

const struct bus_type greybus_bus_type = {
        .name =         "greybus",
        .match =        greybus_match_device,
        .uevent =       greybus_uevent,
        .probe =        greybus_probe,
        .remove =       greybus_remove,
        .shutdown =     greybus_shutdown,
};

int greybus_register_driver(struct greybus_driver *driver, struct module *owner,
                            const char *mod_name)
{
        int retval;

        if (greybus_disabled())
                return -ENODEV;

        driver->driver.bus = &greybus_bus_type;
        driver->driver.name = driver->name;
        driver->driver.owner = owner;
        driver->driver.mod_name = mod_name;

        retval = driver_register(&driver->driver);
        if (retval)
                return retval;

        pr_info("registered new driver %s\n", driver->name);
        return 0;
}
EXPORT_SYMBOL_GPL(greybus_register_driver);

void greybus_deregister_driver(struct greybus_driver *driver)
{
        driver_unregister(&driver->driver);
}
EXPORT_SYMBOL_GPL(greybus_deregister_driver);

static int __init gb_init(void)
{
        int retval;

        if (greybus_disabled())
                return -ENODEV;

        BUILD_BUG_ON(CPORT_ID_MAX >= (long)CPORT_ID_BAD);

        gb_debugfs_init();

        retval = bus_register(&greybus_bus_type);
        if (retval) {
                pr_err("bus_register failed (%d)\n", retval);
                goto error_bus;
        }

        retval = gb_hd_init();
        if (retval) {
                pr_err("gb_hd_init failed (%d)\n", retval);
                goto error_hd;
        }

        retval = gb_operation_init();
        if (retval) {
                pr_err("gb_operation_init failed (%d)\n", retval);
                goto error_operation;
        }
        return 0;       /* Success */

error_operation:
        gb_hd_exit();
error_hd:
        bus_unregister(&greybus_bus_type);
error_bus:
        gb_debugfs_cleanup();

        return retval;
}
module_init(gb_init);

static void __exit gb_exit(void)
{
        gb_operation_exit();
        gb_hd_exit();
        bus_unregister(&greybus_bus_type);
        gb_debugfs_cleanup();
        tracepoint_synchronize_unregister();
}
module_exit(gb_exit);
MODULE_DESCRIPTION("Greybus core driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");